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restricted memcpy to allocators known to not have fancy construct()

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joaquintides
2022-12-12 11:26:12 +01:00
committed by Christian Mazakas
parent 47e205487d
commit 91eddbabe8
1 changed files with 45 additions and 0 deletions
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45
include/boost/unordered/detail/foa.hpp
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@ -31,6 +31,7 @@
#include <cstring>
#include <iterator>
#include <limits>
#include <memory>
#include <tuple>
#include <type_traits>
#include <utility>
@ -1025,6 +1026,47 @@ inline void prefetch(const void* p)
struct try_emplace_args_t{};
template<typename Allocator>
struct is_std_allocator:std::false_type{};
template<typename T>
struct is_std_allocator<std::allocator<T>>:std::true_type{};
/* std::allocator::construct marked as deprecated */
#if defined(_LIBCPP_SUPPRESS_DEPRECATED_PUSH)
_LIBCPP_SUPPRESS_DEPRECATED_PUSH
#elif defined(_STL_DISABLE_DEPRECATED_WARNING)
_STL_DISABLE_DEPRECATED_WARNING
#elif defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable:4996)
#endif
template<typename Allocator,typename Ptr,typename... Args>
struct alloc_has_construct
{
private:
template<typename Allocator2>
static decltype(
std::declval<Allocator2&>().construct(
std::declval<Ptr>(),std::declval<Args&&>()...),
std::true_type{}
) check(int);
template<typename> static std::false_type check(...);
public:
static constexpr bool value=decltype(check<Allocator>(0))::value;
};
#if defined(_LIBCPP_SUPPRESS_DEPRECATED_POP)
_LIBCPP_SUPPRESS_DEPRECATED_POP
#elif defined(_STL_RESTORE_DEPRECATED_WARNING)
_STL_RESTORE_DEPRECATED_WARNING
#elif defined(_MSC_VER)
#pragma warning(pop)
#endif
#if defined(BOOST_GCC)
/* GCC's -Wshadow triggers at scenarios like this:
*
@ -1590,6 +1632,9 @@ private:
#else
std::is_trivially_copy_constructible<value_type>::value
#endif
&&(
is_std_allocator<Allocator>::value||
!alloc_has_construct<Allocator,value_type*,const value_type&>::value)
>{}
);
}